如何在JavaFX中创建动态可调整大小的形状？

Question

我有三个问题：

1. 我想创建带有边界框的可调整大小形状...
2. 我还想知道如何在Pane中选择子对象。
3. 我正在创建多个形状，我想改变其中某些形状的属性，比如填充颜色... 我该怎么做？

谢谢

- Vinod CG

Answer 1

下面的例子将回答您的问题：

• for (1) it uses binding, connecting pane size with rectangle size
• for (2) it adds setOnMouseClick for each rectangle which stores clicked one in the lastOne field.

• for (3) see code of setOnMouseClick() handler

  public class RectangleGrid extends Application {
  
    private Rectangle lastOne;
  
    public void start(Stage stage) throws Exception {
      Pane root = new Pane();
  
      int grid_x = 7; //number of rows
      int grid_y = 7; //number of columns
  
      // this binding will find out which parameter is smaller: height or width
      NumberBinding rectsAreaSize = Bindings.min(root.heightProperty(), root.widthProperty());
  
      for (int x = 0; x < grid_x; x++) {
          for (int y = 0; y < grid_y; y++) {
              Rectangle rectangle = new Rectangle();
              rectangle.setStroke(Color.WHITE);
  
              rectangle.setOnMouseClicked(new EventHandler<MouseEvent>() {
                  @Override
                  public void handle(MouseEvent t) {
                      if (lastOne != null) {
                          lastOne.setFill(Color.BLACK);
                      }
                      // remembering clicks
                      lastOne = (Rectangle) t.getSource();
                      // updating fill
                      lastOne.setFill(Color.RED);
                  }
              });
  
              // here we position rects (this depends on pane size as well)
              rectangle.xProperty().bind(rectsAreaSize.multiply(x).divide(grid_x));
              rectangle.yProperty().bind(rectsAreaSize.multiply(y).divide(grid_y));
  
              // here we bind rectangle size to pane size 
              rectangle.heightProperty().bind(rectsAreaSize.divide(grid_x));
              rectangle.widthProperty().bind(rectangle.heightProperty());
  
              root.getChildren().add(rectangle);
          }
      }
  
      stage.setScene(new Scene(root, 500, 500));
      stage.show();
    }
  
    public static void main(String[] args) { launch(); }
  }
  

- Sergey Grinev